This invention relates to floor panels for use in a raised acces flooring system and more particularly to an air flow floor panel with a high strength to weight ratio.
Raised access flooring systems are used in several situations. When it is necessary that air conditioning, heating and electrical systems be located beneath the floor as opposed to in a plenum area above the ceiling of a room it is necessary that a pedestal type raised access floor system be employed. When the heating and air conditioning plenum is located below this raised access floor it is also necessary that certain of the panels permit air flow therethrough and, although the majority of the floor panels can be solid in these situations, certain of the floor panels must provide air flow into the room above the floor. In addition, in a clean room situation where vertical laminar flow is required the entire floor structure may be required to provide air flow therethrough. In the past, in some instances, a simple non-load bearing register was employed to provide air conditioning and heating to the room. These non-load bearing structures, however, limit the location of office furniture and the like as well as traffic patterns through the room and generally must be located adjacent a wall to remove them from any future pedestrian traffic patterns. In an effort to provide light weight structurally sound floor panels several different construction methods have been employed. In U.S. Pat. No. 3,236,018 to D. C. Graham et al. support was provided by bending portions of the bottom sheet into vertically oriented struts to provide a truss like construction by welding each of the bent portions of the bottom sheet to the top plate. In another construction disclosed in U.S. Pat. No. 3,067,843 to F. N. Rushtoh et al. a plurality of integral underlying spaced bearing bars or ribs of inverted T-shape depend from the floor panel top plate and are supported by a plurality of transverse I-beams which extend perpendicular to the bearing bars. Each of the foregoing prior art structures require a significant number of welds which increases the cost of manufacturing and employ rather heavy gauge steel tp provide sufficient strength and therefore a heavier and more expensive panel to manufacture. A floor panel is needed that is strong enough to support heavy office machinery and be particularly resistant to deformation and deflection under loads of up to 250 pounds per square foot. Furthermore, a high strength to weight ratio is an important criteria even where air flow through a perforated top sheet is necessary.